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Biomedical subjects

T Kubo

Publications and source records attributed to T Kubo.

At least 253 records · Page 14Linked to original sources
PubMed1999

Alterations in organization and transcription of the mitochondrial genome of cytoplasmic male sterile sugar beet (Beta vulgaris L.).

We have constructed a physical map of the mitochondrial DNA of a cytoplasmic male sterile (CMS) sugar beet line, TK81-MS, and compared it with that published for normal fertile sugar beet (cv. TK81-O) to clarify the differences between the CMS and normal mitochondrial genomes. The TK81-MS genome is present as a single circular molecule of 481.8 kb, or as two molecules of 184.9 and 296.9 kb. The CMS genome was found to be highly rearranged relative to the normal mitochondrial genome, with at least fifteen rearrangement and/or inversion events being required to align the two DNAs. Analysis of transcription patterns of known mitochondrial genes and rearranged regions revealed six genes, coxI, coxII, atpA, atp6, rps3, and orf324, whose expression is altered in the CMS line relative to the normal line. Of these six, only the coxI transcript pattern differs between male-sterile and fertility-restored genotypes, making it likely that the coxI locus is involved in mediating CMS in sugar beet.

Base Sequence↗
PubMed1999

Deletion of a large genomic segment in tobacco varieties that are resistant to potato virus Y (PVY).

Recessive alleles (va, va1, va2, etc) of the tobacco Va locus confer resistance to potato virus Y (PVY). To elucidate the mechanism underlying this resistance, we attempted to identify randomly amplified polymorphic (RAPD) markers that reveal polymorphism between two nearly isogenic lines (NILs) that differ in their susceptibility to PVY. Using each of 500 primers and 800 pairs of primers, we identified over 100 RAPD fragments that differed between the NILs. We applied these RAPD primers or primer combinations to an F2 population obtained from a cross between the susceptible line BY4 and the resistant va2-bearing NIL, F55. It was found that only 10 RAPD markers were polymorphic between resistant and susceptible plants. Unexpectedly, these markers were all linked to Va. All 10 RAPD markers were present in all 8 susceptible varieties tested. At least one RAPD marker was not detected in 8 out of 10 resistant varieties. Southern analysis revealed that the sequences of markers were not present in the genomes of resistant varieties, and the markers were found in individually distinct positions on the chromosomes of susceptible tobacco varieties. These results strongly suggest that the resistance conferred by va is due to deletions at the Va locus governing susceptibility to PVY.

Base Sequence↗
PubMed1999

Bleeding risk in unruptured and residual cerebral aneurysms--angiographic annual growth rate in nineteen patients.

Whether and when unruptured aneurysms or aneurysmal rests following incomplete surgery result in subsequent bleeding are major concerns for neurosurgeons. By calculating the annual growth rate of aneurysms in long-term follow-up angiography (partly supplemented with MR-imaging and/or MR-angiography), we attempted to determine the surgical indications for these aneurysms. Long-term follow-up angiography ranging from one to 20 years was carried out on five patients whose ruptured aneurysms had been incompletely occluded, six patients with multiple aneurysms, of which the ruptured ones had been completely obliterated at operation and the small unruptured aneurysms, missed or misdiagnosed, and eight patients with unruptured aneurysms which were asymptomatic or symptomatic. The correlation of annual aneurysm growth rate to subsequent bleeding was investigated. Four out of six fast-growing aneurysms with high annual growth rates (more than 8% increase per year) resulted in subsequent bleeding whereas none of the fourteen slow-growing aneurysms with low annual growth rates (less than 8% increase per year) led to bleeding (Fisher's exact test; p < 0.01). Hypertension, patient age and aneurysmal location showed no significant correlation to the annual growth rate (Fisher's exact test; p > 0.05). This study suggests that aneurysmal rests after incomplete surgery and missed or misdiagnosed multiple or incidental aneurysms which are fast growing have a high possibility of subsequent bleeding and should be operated on as soon as possible.

Aneurysm, Ruptured↗
PubMed1999

Radial-sequence magnetic resonance imaging in evaluation of acetabular labrum.

We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15 degrees -intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion.

Acetabulum↗
PubMed1999

Direct adenovirus-mediated gene delivery to the temporomandibular joint in guinea-pigs.

Adenovirus vector system is expected to be useful for direct gene therapy for joint disease. This study first sought to confirm that foreign genes can be transferred to articular chondrocytes in primary culture. Next, recombinant adenovirus vectors harbouring beta-galactosidase gene (LacZ) was injected directly into the temporomandibular joints of Hartley guinea-pigs to clarify the in vivo transfer availability of the adenovirus vectors. Specifically, recombinant adenovirus harbouring LacZ gene (AxlCALacZ) was injected into the upper joint cavities of both mandibular joints of four male 6-week-old Hartley guinea-pigs. Either the same amount of recombinant adenovirus without LacZ gene (Axlw) suspension (placebo) or the same amount of phosphate-buffered saline solution (control) were injected into the upper joint cavities of both joints of another four male guinea-pigs. At 1, 2, 3 and 4 weeks after injection, the joints were dissected and the expression of delivered LacZ was examined by 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) staining and reverse transcriptase-polymerase chain reaction (RT-PCR). To investigate the expression of transferred gene in other organs, total RNA was extracted from liver, kidney, heart and brain and the expression of LacZ mRNA and 18 S ribosomal RNA were analysed by RT-PCR. Clear expression of LacZ was observed in the articular surfaces of the temporal tubercle, articular disc and synovium of the temporomandibular joints even 4 weeks after injection in the AxlCALacZ-injected group, while no expression was detected in placebo and control groups. Histological examination confirmed that LacZ activity was clearly detected in a few cell layers of the articular surface tissues, which is much more efficient than in a previously study of the knee joint. In the other organs, expression of the delivered transgene was not observed. Based on these findings, direct gene delivery into the articular surface of the temporomandibular joint using the adenovirus vector is feasible as an effective in vivo method.

Adenoviridae↗
PubMed1999

Mouse semaphorin H inhibits neurite outgrowth from sensory neurons.

Mouse semaphorin H (M-semaH) was structurally similar to semaphorin III/D, a mammalian homologue of collapsin 1 which was identified as a collapsing factor for sensory nerves. In this study we investigated the expression patterns of M-semaH mRNA and the protein binding sites in the trunk of mouse embryos. M-semaH mRNA was expressed in the mesenchymal tissues surrounding each dorsal root ganglia. These tissues include the caudal sclerotome and perinotochordal mesenchyme, which were thought to express factors repulsive to axons. M-semaH binding was detected on the spinal nerves. We further investigated, using in vitro co-culture assay, whether M-semaH acted as a chemorepulsive molecule on sensory axons. The results suggested that M-semaH was a candidate for a chemorepellent expressed in the mesenchyme surrounding the sensory ganglia, which is involved in the axonal guidance mechanism of sensory nerves in the trunk.

3T3 Cells↗
PubMed1999

Effects of discrimination difficulty on cognitive event-related brain potentials in patients with cochlear implants.

Cognitive event-related brain potentials (ERPs) recorded during a 2-tone discrimination (oddball) task were examined in 8 patients with cochlear implants. The aim of this study is to investigate the effects of discrimination difficulty formed by 4 conditions of stimulus contrast: the target stimuli were set at 2000, 1500, 1200, or 1100 Hz, and nontarget stimuli were set at 1000 Hz throughout. The averaged ERPs recorded after the target stimuli revealed N100, P200, N200, and P300 peaks, whereas those after the nontarget stimuli showed only N100 and P200 peaks. The peak latencies of the ERP components of early information processings (N100 and P200) were not significantly increased among the 4 conditions. In contrast, the latencies of late cognitive components (N2b and P300, whose peak latencies were longer than 250 msec) and reaction times were significantly increased as target discriminability decreased. In conclusion, early information processings were not delayed by the discrimination difficulty, but cognitive processings were delayed in patients with cochlear implants. Because the N2b amplitude, which is considered to be associated with controlled processings, was much larger than that previously reported from subjects with normal hearing, it is suggested that patients with cochlear implants make a considerable effort to process their poor auditory information.

Adult↗
PubMed1999

Pelvic malignant mixed mesodermal tumor of uncertain origin: a case report.

Extra-uterine, and especially extragenital, malignant mixed mesodermal tumors (MMMT) are very rare. A large intrapelvic tumor resected from a 56-year-old woman was investigated with morphological and immunohistochemical methods. A large, soft and fragile tumor was located in the pelvic space. The tumor showed high cellularity and was biphasic; it consisted of an admixture of adenocarcinoma and various kinds of sarcomas. The latter were comprised of high-grade endometrial stromal sarcoma, pleomorphic sarcoma, and chondrosarcoma. The pleomorphic sarcoma showed a storiform pattern. The periodic acid-Schiff-positive eosinophilic hyaline droplets and globules in multinucleated giant cells revealed a typical ring-like or peripheral staining for alpha-1-antitrypsin and alpha-1 antichymotrypsin. We considered this case to be pelvic MMMT of uncertain origin, heterologous type.

Combined Modality Therapy↗
PubMed1999

Developmental localization of semaphorin H messenger RNA acting as a collapsing factor on sensory axons in the mouse brain.

Semaphorins/collapsins, a family of genes with a semaphorin domain conserved from insects through to mammals, are believed to be involved in axon guidance during neuronal development. We report the expression patterns of mouse semaphorin messenger RNAs. Among secreted semaphorins, mouse semaphorin H is structurally most similar to semaphorin III/D, the first semaphorin identified as a collapsing factor for sensory axons. However, its expression patterns apparently differ from those of semaphorin III/D. The messenger RNAs are distributed in the brain widely but unevenly during development, in particular, in the main olfactory bulb, hippocampus and pontine nucleus. In the trunk, the expression level is high in mesodermal tissues surrounding the dorsal root ganglia, while it is low in the spinal cord. Moreover, we examined whether this molecule has activity to collapse growth cones of sensory neurons, as well as semaphorin III/D. Mouse semaphorin H collapsed growth cones of sensory neurons of the dorsal root ganglion in a dose-dependent manner, and anti-neuropilin antibodies inhibited this activity. Taken together, these results suggest that mouse semaphorin H can function as a chemorepellent to guide sensory peripheral nerves, most likely via neuropilin as a receptor.

Amino Acid Sequence↗
PubMed1999

Osteoporosis influences the late period of fracture healing in a rat model prepared by ovariectomy and low calcium diet.

To elucidate the influence of osteoporosis on the fracture healing, we produced a rat osteoporosis model by ovariectomy and by maintaining a low calcium diet; and monitored the healing process radiographically, histologically, and biomechanically for 12 weeks. Radiologic, histologic and biomechanical findings of the fracture areas 6 weeks after making the fractures were almost identical in both the osteoporosis group and the control group. However, 12 weeks after making the fractures, newly generated bones in the osteoporosis group showed histological osteoporotic changes and their bone mineral density on the fracture site decreased. These findings show that estrogen-deficient and low calcium conditions greatly affect the bone in the later period of the healing process, but do not affect remarkably the early healing period. This is clinically important when we consider fracture treatments for patients with osteoporosis due to menopause.

Animals↗
PubMed1999

The effects of hyaluronan on matrix metalloproteinase-3 (MMP-3), interleukin-1beta(IL-1beta), and tissue inhibitor of metalloproteinase-1 (TIMP-1) gene expression during the development of osteoarthritis.

OBJECTIVE: To assess the influence of intra-articular injection of hyaluronan (HA) on expression of matrix metalloproteinase-3 (MMP-3), interleukin-1beta(IL-1beta), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in cartilage and synovium during the process of osteoarthritis (OA). DESIGN: Eighteen mature New Zealand white rabbits underwent unilateral anterior cruciate ligament transection (ACLT) and were divided into two groups. The first group (HA injection group) received 0.3 ml of intra-articular HA injections into the ACLT knees 4 weeks after transection, once a week for 5 weeks as per clinical treatment presently utilized. The animals in the second group (no injection group) were not injected after ACLT. At death, 9 weeks following surgery, synovium and cartilage were harvested and total RNA was extracted. Gene expressions of MMP-3, IL-1beta and TIMP-1 were analyzed using reverse transcription-polymerase chain reaction (RT-PCR) for each subgroup created according to morphological grade of OA. RESULTS: The extent and grade of cartilage damage in the HA injection group was less severe than in the no injection group. In synovium, expression of MMP-3 and IL-1beta mRNA was suppressed in the mild grades of OA in the HA injection group. HA treatment had either no effect on MMP-3 expression in cartilage at all grades of OA or on enhanced MMP-3 and IL-1beta expression in synovium at a progressed grade. No effect of HA treatment on TIMP-1 expression was observed in either cartilage or synovium. CONCLUSIONS: These results suggest that one of the mechanism of therapeutic effect of HA is down-regulation of MMP-3 and IL-1beta in synovium during early development of OA.

Animals↗
PubMed1999

Ki-67 positive fractions in benign and malignant thyroid tumours: application of flow cytometry.

We investigated the DNA ploidy pattern, cell cycle and the percentage of Ki-67 positive fractions in fresh surgical material from 17 benign and 33 malignant thyroid tumours using flow cytometry. DNA aneuploidy was not seen at all in benign tumours, but was seen in 3 out of 33 malignant tumours, suggesting that detection of DNA aneuploidy indicates malignancy, although the detection sensitivity was low. Regarding the cell cycle, there was no difference in the percentage of S-phase fractions (SPF) or G2 plus M phase fractions (G2M) between benign and malignant tumours. However, the percentage of Ki-67 positive fractions in malignant tumours (39.9 +/- 3.9%) was significantly higher than that in benign tumours (9.4 +/- 2.1%), indicating that malignant thyroid tumours contained a large population of G phase cells. When a cut-off value of 20%, was used for Ki-67 positive fractions, sensitivity was 82%, specificity was 88% and accuracy was 84% for the diagnosis of malignant tumours. Although this study was carried out on surgically derived materials, it is possible that flow cytometric analysis of fine needle aspiration-derived materials may have a place in preoperative histopathological assessment of thyroid tumours.

Adenocarcinoma, Follicular↗
PubMed1999

Rotation vector analysis of eye movement in three dimensions with an infrared CCD camera.

We have developed a new technique for analyzing the rotation vector of eye movement in three dimensions with an infrared CCD camera based on the following four assumptions; i) the eye rotates on a point; ii) the pupil edge is a circle; iii) the distance from the center of eye rotation to pupil circle remains unchanged despite the rotation; iv) the image of the eye by the CCD camera is projected onto a plane which is perpendicular to the camera axis. After taking digital images of voluntary circular eye movements, we first constructed a three-dimensional frame of reference fixed on the orbita of the subject wearing a goggle equipped with an infrared CCD camera, and determined the space coordinates of the center of eye rotation, the center of the pupil, and an iris freckle. We then took digital images of the eye movements during a saccade or vestibulo-ocular reflex (VOR) and analyzed the axis and angle of the eye movements by the trajectories of the center of the pupil and the iris freckle. Finally, Listing's plane of saccade and the gain and the phase of VOR were obtained. The suitability of this technique is examined.

Adult↗
PubMed1999

Interaction of cationic alpha-helical peptide with phosphorothioate DNA hybrid.

Synthetic amphiphilic alpha-helix peptides were found to bind to stabilize double or triple stranded DNA. The stabilization effect was significant for cationic alpha-helix peptides which indicated the importance of electrostatic interaction of positive charge of peptide and negative charge of DNA. It should be also pointed out that hybrid double or triple helical complexes containing phosphorothioate oligonucleotide were stabilized to a larger extent respect to phosphodiester oligonucleotides. Since it was shown that cationic amphiphilic alpha-helix peptide accelerate membrane permeability of DNA, the present study can provide a solution for the problems of antisense or triplex oligonucleotide in their practical application.

Amino Acid Sequence↗
PubMed1999

Interaction of amphiphilic cyclic peptide with double and triple stranded DNA.

It was found that Gramicidin S (GS) with intramolecular antiparallel beta-sheet structure could bind to and thermally stabilize double and triple stranded DNA. UV melting study revealed that GS stabilized mixed sequence dsDNA in the presence of Mg2+ (deltaTm = +6.0) but it stabilized dsDNA with homosequence only in the absence of Mg2+. It should be pointed out that GS specifically stabilized the third strand (Hoogsteen base pair) but not double strand (Watson-Crick base pair) in triple helix DNA.

Base Pairing↗
PubMed1999

Preliminary report on usefulness of magnetic resonance imaging for outcome prediction in early-stage Legg-Calvé-Perthes disease.

The usefulness of magnetic resonance imaging (MRI) for predicting prognosis was evaluated in 11 patients with unilateral early-stage Legg-Calvé-Perthes disease who were treated with a non-weight-bearing abduction brace. Six to 10 months after disease onset, severity of cartilage hypertrophy and physeal curvature of the femoral head were scored on MRI. Femoral head deformity was radiographically evaluated. Among five patients whose MRI score was 8 or greater, radiographic evaluation after the treatment was "poor" or "fair," whereas evaluation for the other six patients whose MRI score was 7 or less was "good." The MRI scores indicated possible occurrence of femoral head deformation. Treatment method should be considered carefully when the MRI score is high.

Braces↗